The present invention relates to training and rehabilitating brain function, and in particular, to the use of hemi-lens to accomplish this purpose.
Brain injury, such as Cerebral Vascular Accident (stroke), closed head injury, penetrating head wounds, and invasive growths can generate a variety of sensory/perceptual and other cognitive disturbances that significantly impact the ability of individuals to maintain independence in their environments. When this insult occurs in the posterior regions of the brain, especially the parietal and/or occipital lobes, a change in the functioning of the visual perceptual system can occur. These sensory/perceptual disturbances involve inattention to visual stimuli to a varying degree, from mild inattention to details to complete loss of recognition of visual information in a given visual field. In some instances, perception of the visual field disappears completely.
Rehabilitation of the patient with a visual perceptual defect is limited. Most techniques involve behavioral and/or cognitive training directed at focused extra attention to the visual field that has been disrupted. The results of this type of rehabilitation have been successful, but limited.
Recent evidence showing that attention plays an essential role in almost all other brain functions including motor functioning in stroke patients with hemiparesis or hemiplegia, suggests that any technique that can improve attention related to brain injury might help in the recovery of many non-vision related brain functions. In addition, some research has established a relationship between hemispheric attention and visual processing in the dysfunction of developmental reading disorder, the most common type of learning disability.
Furthermore such improvement in brain function could also be effective in visual training in non-medical settings. For example, baseball batters use asymmetric visual information when standing at the plate judging pitches. Isolating the field that captures the pitcher and pitch, and blocks the catcher, umpire, and other distractions might significantly improve batting performance.
Contact lens, glasses and the like are known in which areas of the lens are rendered opaque or semi-opaque for the purpose of correcting defects in vision or to shield the eye from damage.
Harrell, E. H., T. Kramer-Stutts, and A. J. Zolten, xe2x80x9cPerformance of Subjects with Left Visual Neglect after Removal of the Right Visual Field Using Hemifield Goggles,xe2x80x9d Journal of Rehabilitation, (October/November/December 1995), pp.l 46-49, discloses improved performance with visual input directed to a neglected field when the non-neglected field is occluded. Harrell et al. disclose complete occlusion of the visual field directed to one hemisphere of the brain.
Harrell et al. disclose changing the amount of visual field input by adjusting the Velcro strips which provide the occlusion over the goggles used in the experiment described in the article. Harrell et al. do not, however, disclose the use of a series of lenses of varying degrees of opacity, such as semi-opaque areas, in the course of visual retraining.
While Harrell et al. suggest that in the future a procedure using contact lenses might be preferable to goggles, they conclude that this would be expensive and probably not feasible for practical applications in rehabilitation.
One of the problems in using contact lens having occluded areas is that the contact lens must sit on the eye without rotation. Various techniques are known for maintaining the position of a contact lens without rotation. For example, such techniques are disclosed in U.S. Pat. Nos. 4,324,461; 5,483,304; 5,502,518; and 5,570,142. Also, various techniques are known for manufacturing contact lenses with opaque areas.
The present invention is method of using a hemi-lens contact lens product to selectively block visual sensory input to a specific portion of the brain. The term xe2x80x9chemi-lensxe2x80x9d is used herein to refer to a lens having portions of the lens occluded by opaque or semi-opaque material.
The xe2x80x9cblindingxe2x80x9d of the sensory-blocked portion of the brain forces processing of all primary visual information to the remaining portions of the brain. This technique is useful in the rehabilitation of visual field defects, training of brain function and for other purposes.
For example, if the left halves of each of a pair of contact lenses are rendered opaque (e.g., by patching the left half of each lens with black non-translucent contact lens plastic) visual processing is forced to the right hemisphere of the brain thereby stimulating that area of the brain. Occluding the right halves of each of a pair of contact lenses with opaque material would stimulate the opposite hemisphere.
Specific areas of the brain are targeted by selectively blinding portions of each of a pair of contact lenses over more or less than a full hemisphere. For example, a particular quarter segment of each lens could be rendered clear or the remaining xc2xe segment could be rendered opaque. Various combinations of blocked portions of the contact lenses may therefore be utilized to force visual processing to a particular portion of the brain that is thereby stimulated. Each contact lens is weighted or otherwise constructed so that the lenses sit on the eye without rotating.
The method of using the hemi-lens to rehabilitate a patient with a visual defect or training specific visual processing areas consists of having the patient perform visual and non-visual tasks constructed to activate processing in the targeted portion of the brain. A graduated series of hemi-lenses are constructed of semi-transparent material of varying degrees of opacity to allow the patient""s visual system to adapt in stages to the rehabilitated balance between intact visual processing and relearned visual processing.
It is therefore an object of the present invention to provide for a method of using a contact lens product having occluded segments to force visual processing to targeted areas of the brain to encourage rehabilitation and training of such targeted areas.
It is a further object of the present invention to provide for such a method employing a series of contacts lens having graduated degrees of opacity to allow the patient""s vision to adapt in stages to rehabilitation and training.
These and other objects and advantages of the present invention will be apparent from a consideration of the following detailed description of the preferred embodiments in conjunction with the appended drawings as described following.